In a communication system, a transmitting unit divides each of latitude data and longitude data of a current location transmitted from a GPS receiver, at a predetermined digit position, into high order data and low order data. The transmitting unit makes a high order frame containing the high order data of each of the latitude data and the longitude data, and a low order frame containing the low order data of each of the latitude data and the longitude data, and transmits the high order frame and the low order frame, independently to a CAN bus. A receiving unit combines the high and low order data regarding the latitude data together, and further combines the high and low order data regarding the longitude data, extracted from the received high and low order frames in order to reconstruct the latitude data and the longitude data of the current location.